Earnings per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator:
Net income from continuing operations	$ 6,527	$ 6,633	$ 30,930	$ 28,667
Net income attributable to non-controlling interests	13	48	154	124
Net income attributable to controlling interest from continuing operations	$ 6,514	$ 6,585	$ 30,776	$ 28,543
Denominator:
Denominator for basic earnings per share (in shares)	22,756,000	22,691,000	22,744,000	22,675,000
Effect of dilutive securities [Abstract]
Employee stock options and restricted stock units (in shares)	211,000	252,000	218,000	266,000
Supplemental Executive Retirement Plan (in shares)	115,000	110,000	115,000	108,000
Denominator for diluted earnings per share (in shares)	23,082,000	23,053,000	23,077,000	23,049,000
Antidilutive options (in shares)	323	1,072	573	822